A fire that damaged six units in a Centralia apartment building in January and resulted in the evacuation of a family trapped in an upstairs unit was caused by “smoking material” that ignited a couch, according to a report from the Riverside Fire Authority.

The fire was first reported at about midnight Jan. 17 at an apartment building in the 1400 block of Lewis Street in Centralia.

“The fire originated on the first floor of the complex and trapped the occupants of the apartment unit above the fire,” according to a news release from the RFA.

Fire crews rescued five trapped occupants, including two children. The children were evacuated with a ladder and the adults walked out of the apartment after the fire was extinguished, according to an earlier report of the RFA.

No smoke detectors were present, according to the RFA.

A total of seven occupants were displaced and no injuries were reported. Six units were damaged, according to the RFA.

A fire investigation team made up of members of the RFA and the Centralia Police Department concluded that the cause of the fire was accidental, resulting from smoking materials igniting a couch while the apartment’s occupant slept.